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991.
Origin of Listwanite in the Luobusa Ophiolite, Tibet, Implications for Chromite Stability in Hydrothermal Systems 总被引:1,自引:0,他引:1
ZHANG Lan YANG Jingsui Paul T. ROBINSON XIONG Fahui CHEN Yanhong LAI Shengmin CHEN Mei 《《地质学报》英文版》2015,89(2):402-417
Listwanite from the Luobusa ophiolite,Tibet,forms a narrow,discontinuous band along the eastern part of the southern boundary fault. We undertook a detailed petrographic and geochemical study to understand the mineral transformation processes and the behaviour of major and trace elements during listwanite formation. Three alteration zones characterized by distinct mineral components and texture are recognized and,in order of increasing degree of alteration,these are: zoneIII is rich in serpentine minerals; zoneII is rich in talc and carbonates; and zoneI is mainly composed of carbonates and quartz. Geochemical data for the three alteration zones show significant modification of some major and trace elements in the protolith,although some oxides show linear correlations with Mg O. Gold mineralization is recognized in the Luobusa listwanite and may signify an important target for future mineral exploration. Gold enrichment occurs in both zoneI and zoneIIand is up to 0.91 g/t in one sample from zoneI. We show that CO2-rich hydrothermal fluids can modify both the occurrence and composition of chromite grains,indicating some degree of chromite mobility. Low-Cr anhedral grains are more easily altered than high-Cr varieties. The compositions of chromite and olivine grains in the listwanite suggest a dunite protolith. 相似文献
992.
XIONG Fahui YANG Jingsui Robinson T.PAUL XU Xiangzhen BA Dengzhu LI Yuan LIJinyang ZHANG Zhongming RONG He 《《地质学报》英文版》2015,89(Z2):99-100
<正>The first diamonds from ophiolite were found in peridotite of Luobusa ophiolite along Yarlung Zangbu suture zone in Tibet,China(IGCAGS,1981),and then more and more diamonds found in harzgurgite(Bai et al.,1993;Yang et al.,2007a;Robinson et al.,2014;Xu et al., 相似文献
993.
XIONG Fahui YANG Jingsui Robinson T PAUL Dilek YILDIRIM CHEN Yanhong XUXiangzhen LIU Zhao TIAN Yazhou ZHOU Wen LAI Shengming ZHANG Lan 《《地质学报》英文版》2015,89(Z2):101-101
<正>Diopside and magnetite exsolutions occur as oriented intergrowths within olivine of the lower Cr~#dunite in the Dongbo ophiolite,Tibet.The fresh lower Cr~#dunite has a mineral assemblage of olivine,spinel and diopside.The Fo content of its olivine is 90–92,which is lower than that of the higher Cr~#dunite lenses(Fo92-Fo94)without 相似文献
994.
YANG Jingsui WIRTH Richar XIONG Fahui TIAN Yazhou HUANG Zhu ROBINSON Paul T. DILEK Yildirim 《《地质学报》英文版》2015,89(Z2):108-109
<正>Ophiolites are fragments of ancient ocean lithosphere emplaced on continental margins,in island arcs or in accretionary prisms,and have long been studied to better understand the evolution of ocean basins and collision of tectonic plates,the processes of mountain building and the occurrence of valuable ore bodies,such as podiform 相似文献
995.
<正>The Yarlung Zangbo Suture Zone(YZSZ)to the west of Saga is divided into two sub-belts,namely the south subbelt and the north sub-belt.The Saga ophiolite is mainly composed of peridotites,gabbro,diabase and lava.In this paper,we report a suite of alkaline basalt to the south of the Saga ophiolite,which extends NWW along an outcrop 相似文献
996.
XIONG Xiaohui XIAO Jiafei HU Ruizhong WANG Jian WANG Yi WANG Xinsong DENG Qi 《《地质学报》英文版》2015,89(6):2012-2029
This paper presents a set of bulk geochemical and mineralogical data from a paleoweathering profile located in Zunyi District, Northern Guizhou, China. It was formed at the top of the Hanjiadian Formation of the Lower Silurian. A truncated, argillic, gleyed, kryptic paleospodosol is recognized in the paleoweathering profile. Ratios of immobile elements (Ti/Zr, Ti/Al) and their binary (e.g., Nb vs. Zr/TiO2 and Th/Sc vs. Zr/Sc), triangular diagrams (La-Th-Sc, Th-Sc-Zr/10, Zr-Cr-Ga) reflect that the Gaojiayan paleosol is the product of in-situ weathering of gray-green silty mudstone of the underlying Hanjiadian Formation. Mass balance calculations indicate K enrichment and Na enrichment in the upper and lower portions of paleosol, respectively. These findings both are the results of transgression, which brings substantial concentrations of such elements as K, Na, and Sr. In particular, K enrichment is achieved by the illitization of kaolinite. The biological processes of terrestrial vascular plants also enhance K concentration, especially at the top of the paleosol. Na enrichment is a consequence of albitization and/or adsorption by clay minerals through cation exchange. The mass distributions and relative mass changes of rare earth elements (REEs) in the studied profile display characteristics of vertical zonation. Three peaks in total REEs content are observed, indicating two paleoclimatic or paleoenvironmental changes. Mineralogical characteristics indicate that the paleoclimate changed first from warm and humid to cold and dry and later, to dry and lightly warmer. The corresponding soil environment varies from weakly acidic to strongly alkaline and later, to weakly acidic. Mass translocation characteristics of REEs and several transition metals suggest that the Gaojiayan paleosol may have undergone top erosion. 相似文献
997.
<正>The Purang ophiolite,which crops out over an area of about 650 km~2 in the western Yarlung-Zangbo suture zone,consists chiefly of mantle peridotite,pyroxenite and gabbro.The mantle peridotites are mostly harzburgite and minor lherzolite that locally host small pods of dunite.Some pyroxenite and gabbro veins of variable size occur 相似文献
998.
GUO Guolin YANG Jingsui PAUL T. Robinson XIONG Fahui XU Xiangzhen LIU Xiaodong LIJinyang LIU Zhao 《《地质学报》英文版》2015,89(Z2):16-17
<正>1 Introduction Platinum-group elements(PGE)are mainly concentrated in some specific minerals known as PGMs,which commonly occur in podiform chromites of ophiolites.In-situ PGM assemblages in chromites can provide valuable information on the physico-chemical nature of the parental melt(s)from which chromitite 相似文献
999.
JIANG Zhenxue TANG Xianglu LI Zhuo JI Wenming YANG Wei YUAN Yuan WANG Pengfei and XIONG Fengyang 《《地质学报》英文版》2015,89(Z1):251-252
<正>Shale gas exploration have yielded remarkable achievements recently in China,and four national demonstration areas for shale gas exploration and production have been established respectively as FulingJiaoshiba,Changning-Weiyuan,Zhaotong and Yanchang.During recent few years,nearly 400 wells have been drilled including 143 exploratory wells(vertical wells)and 相似文献
1000.
HUANG Zhu YANG Jingsui ZHU Yongwang XIONG Fahui LIU Zhao ZHANG Zhongming XU Wei 《《地质学报》英文版》2015,89(Z2):30-31
<正>Previously reported in the Mesozonic Tibet and the early Paleozoic Polar Ural,Russia,diamond and other deep minerals are found in ophiolite mantle peridotite chromite that need to be reconsidered ophiolite and chromite traditional understanding of the causes of shallow.The ophiolitic chromitite can be divided two classes,the high-Cr chromitite and high-Al chromitite. 相似文献